Yes, coal-fired power plants are the biggest emitters of mercury into the environment. This is because mercury is naturally found in coal. Coal-fired power plants emit about 50 tons of mercury every year.

The second biggest emitter of mercury are cement kilns. All the cement kilns combined in the United States pump out about 23,000 tons of mercury every year. The cement manufacturing process involves the use of coal and limestone – another natural source of mercury.